Sure, an HMO license is required when renting to more than 4 unrelated people (so 5+ basically) in Coventry.

There is also selective licensing for some Councils which is area specific, but that is not Government HMO regulations/Licensing. Each Council has different rules but it is not a Government law that you need an HMO license to rent to 3 people or even 4 unrelated people as at the time of this post.